The present invention relates to a data bus connector, and more particularly, but not by way of limitation, to a SCSI data bus connector that can operate either as a single-ended connector or a differential connector, and can reconnect a data bus originally connected to an embedded controller to an user added controller.
Today""s businesses are becoming more and more dependent upon computer systems, including network computer systems, for their day-to-day operations As can be appreciated, the requirement for minimum down-time of these computer systems is imperative, especially in network computer systems, where many users can be affected when a single component in the systems fails.
Some of the existing computer technologies have started utilizing xe2x80x9chot pluggablexe2x80x9d components in the computer system. One such example is redundant power supplies, whereby if one supply fails or needs replacing, the power to the computer system is maintained by the second power supply, and the computer system does not need to be powered down while the other power supply is being repaired or replaced In addition to hot pluggablility, modularity of components is also being implemented. For example, a multiprocessor computer system will have all of the processors implemented into a single module, the media components implemented into another module, and the input/output components implemented into still another module. In this type of computer system each of the individual modules can be removed from the computer chassis for maintenance or upgradability. An example of one such computer system is described in patent application entitled xe2x80x9cComputer Chassis Assembly with a Single Center Pluggable Midplane Boardxe2x80x9d, invented by Kurt Manweiler, Mike Sanders and Tom Hardt, filed on the same day herewith, and assigned to Compaq Computer Corp., which is incorporated in its entirety herein. In this computer system, a processor module, media module, I/O module and power supplies are all interconnected with a single center pluggable midplane board. It is designed so that no ribbon cables are required to interconnect any of the modules In the I/O module, an embedded Ultra2 SCSI (LVD) interface is utilized to help minimize the form factor of the computer chassis. However, one problem with an embedded SCSI interface arises when a user wants to implement a SCSI controller other than the embedded one. A ribbon cable is needed to connect the added SCSI controller with the corresponding drives to be controlled. The ribbon cable would have to traverse the midplane board, thereby defeating the advantages of the modularity of the computer system. Additionally, if the added SCSI is of a different type, the existing data bus may not be compatible
Therefore, as can be appreciated there is a need for a interconnect connector that can implement a user added controller rather than an embedded controller without using cables that cross the module boundaries, and that is also backward compatible with other types of controllers
The present invention overcomes the above identified problems as well as other shortcomings and deficiencies of existing technologies by providing a connector that can be connected directly into the data bus and that can reconnect the data bus with a user added controller, and is further backward compatible with other versions of controllers.
The present invention further provides a computer system with various component modules. The modules are interconnected with a single midplane board, which eliminates the need for ribbon cables to interconnect between the modules. One of the modules includes an embedded controller and associated data bus. An in-line connector is coupled in the data bus which receives either a jumper connector or an interconnect connector. The interconnect connector intercepts the data bus from the embedded controller and transfers connection to a user added controller. The interconnect connector can operate in three modes, a single ended mode, a LV differential mode, and an HV differential mode The interconnect connector includes logic circuitry that determines the signaling environment and places the interconnect connector in the appropriate mode. If the logic circuitry detects a non LVD signaling environment, a quick switch, which is connected to one wire of each data bus pair, is closed, thereby grounding the one wire on each pair. If the logic circuitry detects an LV differential signaling environment, the quick switch places the quick switch in an open position, disconnecting the one wire of each pair of the data bus from ground.